Don't need a restricted shotgun for your application - Rifle sighted pump would do adequately, with ammo of modest recoil.
Reducing recoil is always a balance of ammo selection, weight of firearm and a really good recoil pad.
I used to recommend an Ithaca Deerslayer, but now, other makers produce such rifle sights on a smoothbore.
If the primary user is of smaller stature, shorten the buttstock appropriately.
Almost anyone can learn to shoot a shotgun with rifle sights adequately for defense from predators of all kinds, but practice is essential.